TWI424575B - A solar cell having an electrode of a micrometer or micrometer or lower conductive line - Google Patents

Description

Solar cell with electrodes of micron or micron conductivity

The present invention relates to a solar cell, and more particularly to a solar cell having electrodes of micron or micron conductivity.

Referring to FIG. 1, a current thin film solar cell 1 includes a substrate 11, a lower electrode layer 12 formed on the substrate 11, a photo-generated layer 13 formed on the lower electrode layer 12, and a photo-generated layer disposed thereon. The upper electrode layer 14 on the layer 13, the photo-generated layer 13 excites the charge carriers by the photovoltaic effect when the light is irradiated to generate a photocurrent, and the photoelectric generated by the combination of the lower electrode layer 12 and the upper electrode layer 14 Flow out to output, application.

Since the excited charge carriers need to be moved in the photoelectric generating layer 13 for a certain distance before being "captured" by the upper and lower electrode layers 12, 14 and then outputted, during the movement in the photoelectric generating layer 13 The excited charge carriers have a good chance to recombine, and the longer the distance traveled, the higher the probability of charge carrier recombination. Therefore, for the current thin film solar cell 1, since the substrate 11, the lower electrode layer 12, the photo-generated layer 13, and the upper electrode layer 14 are both flattened, the charge is generated when the photo-charge is excited. The distance that the sub-movement moves in the photo-generation layer 13 is relatively long, and there is a high probability of recombination, resulting in a photocurrent that is actually output by the upper and lower electrode layers 12, 14 being much lower than expected.

Therefore, for the thin film solar cell 1, how to reduce the moving distance of the charge carriers in the photoelectric generating layer 13 and reduce the recombination rate of the charge carriers to improve the photocurrent output efficiency, thereby improving the overall power generation efficiency of the solar cell, It is a technical bottleneck that needs to be broken.

Accordingly, it is an object of the present invention to provide a solar cell having an electrode having a micron- or micro-scale conductive line which can reduce the charge carrier recombination rate to enhance the photocurrent output efficiency.

Thus, the solar cell of the present invention having electrodes of micron- or micro-scale conductive lines comprises a substrate, a lower electrode, a photo-generation body, and an upper electrode.

The lower electrode is formed on the substrate as a conductive material, and includes a substrate, and a plurality of conductive wires of a micrometer order or less, and at least a portion of each of the conductive wires is connected to the substrate.

The photoelectric generating body is formed upward from the substrate and covers the conductive lines, and generates a photocurrent by a photovoltaic effect when illuminating.

The upper electrode is formed on the photoelectric generating body and is electrically conductive, and the lower electrode cooperates with each other to output a photocurrent to the outside.

The utility model has the advantages that: by the bottom electrode structure including the substrate and the plurality of conductive wires, the moving distance of the charge carriers in the photoelectric generating body is greatly reduced to greatly reduce the composite probability and improve the photocurrent output efficiency.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 2, a first preferred embodiment of the solar cell of the present invention having electrodes of micron or sub-scale conductive lines comprises a substrate 2, a lower electrode 3, a photo-generation body 4, and an upper electrode 5.

The substrate 2 includes a light transmissive substrate 21 and an anti-reflection layer 22 formed on the bottom surface of the substrate 21. The anti-reflection layer 22 greatly reduces the amount of light that is left after the incident light is reflected, thereby further reducing the amount of light that is left after the incident light is reflected. Increasing the amount of incident light entering the photo-generation body 4, preferably, the substrate 21 is made of a light-transmitting material, such as a transparent light-transmitting material such as transparent conductive glass (TCO), soda glass, potassium glass, or quartz, or It is composed of a flexible flexible light-transmitting material such as polyetherimide (PET), polycarbonate (PC), or polyethylene naphthalate (PEN), so that the solar cell obtained in the present embodiment can also be The bottom surface of the substrate 21 receives light, and the amount of incident light is increased by the anti-reflection layer 22, thereby increasing the photon absorption efficiency of the photoelectric generator 4.

The lower electrode 3 is formed of a conductive material on a top surface of the substrate 21 opposite to the anti-reflective layer 22, and includes a substrate 31, and a plurality of conductive lines 32 of a micrometer order or less. At least a portion of a conductive wire 32 is connected to the substrate 31. In the present embodiment, each of the conductive wires 32 is connected to the substrate 31 at one end and the free end is formed at the other end.

In this example, the conductive lines 32 are formed on the substrate 31 by anodizing the aluminum oxide film having a plurality of pores of a micron order or less, and then using a conductive material. After the aluminum oxide film is removed after molding in the holes, it will be formed as shown in FIG. 2, and each of the conductive wires 32 is connected upright to the substrate 31. The material type of the conductive wire 32 is selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (Indium Zinc Oxide, IZO), and aluminum zinc oxide (Aluminium Znic Oxide, AZO). Material, or selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), indium (In), tin (Sn), zinc (Zn), gold (Au), silver (Ag), It is composed of a conductive metal material such as aluminum (Al) or manganese (Mn).

Referring to FIG. 3, it is worth mentioning that if the conductive lines 32' are grown by chemical vapor deposition (CVD), physical vapor deposition (PVD), or electrochemical plating, the substrate 2 is first used. After forming the substrate 31, the conductive lines 32' are formed upwardly and angularly from the substrate 31, wherein any of the conductive lines 32' may be up and connected to the substrate at an angle of 90 degrees. 31, or the substrate 31 is connected obliquely upwards and less than 90 degrees, and the conductive lines 32 are grown by chemical vapor deposition (CVD), physical vapor deposition (PVD), electrochemical plating. At the same time, a conductive film is formed simultaneously between the conductive lines 32', as shown in FIG.

The photoelectric generating body 4 is formed upward from the substrate 31 and covers the conductive lines 32, and includes a first type semiconductor 41 and a second type semiconductor 42 which are doped to form a PN junction. And a dye absorbing layer 43 interposed between the first type semiconductor 41 and the second type semiconductor 42. The first type semiconductor 41 and the second type semiconductor 42 cooperate to generate a photocurrent by a photovoltaic effect when illuminated. The dye absorbing layer 43 increases the probability of the junction structure absorbing photons when illuminated.

It is to be noted that the first type semiconductor 41 is composed of an N-type doped or P-type doped semiconductor material, and the second type semiconductor 42 is selected to be P-type doped or corresponding to the first type semiconductor 41. It is composed of an N-type doped semiconductor material. In this embodiment, the first type semiconductor 41 is an N-type material, and the second type semiconductor 42 is a P-type material. In addition, when the first type semiconductor 41 is a P-type material, the second type semiconductor When 42 is an N-type material, the above-mentioned combination can form a junction structure, and when combined with light, a photocurrent is generated by a photovoltaic effect. In addition, the dye absorbing layer 43 is a metal complex dye selected from the group consisting of a Ru-bipyridine (N3) series, a N719 dye, a N749 (Black Dye) dye, or a violet, coumarin, cyanine, or the like. Rhodamine and other B series dyes. In this example, the dye absorbing layer 43 is formed by immersing various dye solutions (alcohol and dye) which have been prepared, and then taking them out and drying them at room temperature.

In addition, since the photoelectric generating body 4 is formed upward from the substrate 31 and covers the conductive lines 32, the surface of the photoelectric generating body 4 is substantially uneven and has a high and low undulating surface, so that the illumination can be greatly increased. The area in turn greatly increases the probability of inducing charge carriers.

Referring to FIG. 4, the upper electrode 5 is formed on the photoelectric generating body 4 and is electrically conductive, and the lower electrode 3 cooperates with each other to output a photocurrent to the outside. In this example, the upper electrode 5 includes a photo-generation body. 4 electrically connected light-transmitting conductive layer 51, and an electrode film 52 disposed on the light-transmitting conductive layer 51 for wiring to output current to the outside, wherein the light-transmitting conductive layer 51 is made of, for example, indium tin oxide The indium zinc oxide, the aluminum zinc oxide, the fluorine tin oxide, and the like are permeable to light and have a conductive material. The electrode film 52 is made of a metal material such as gold, silver, aluminum, aluminum/nickel, or preferably. The electrode film 52 can be a fishbone type as shown in FIG. 4, so that when the light is incident, the light source blocked by the opaque electrode film 52 is reduced, and the incident area of the light is increased, thereby increasing the generation of the photocurrent.

The solar cell of the present invention having the electrode of the micron or micron conductive wire is illuminated by the substrate 31 of the lower electrode 3, and the three-dimensional structure of the plurality of conductive wires 32 extending upward from the substrate 31 is supplemented by the flat film body. , effectively reducing the distance that the generated charge carriers move in the photoelectric generating body 4, thereby reducing the probability of recombination during the moving process, thereby improving the photocurrent actually outputted by the upper and lower electrodes 3, 5, and improving the overall Photocurrent output performance.

Referring to FIG. 5, it is to be noted that the solar cell of the present invention having the electrode of the micron or micron conductive line can greatly increase the light absorption rate when the light is applied in combination with the application of the antireflection layer and the reflective layer, and further The overall photocurrent output performance is improved. In this example, the substrate 21 is permeable to light. When the anti-reflective layer 22 is a light receiving surface and is unilaterally received, between the photoelectric generating body 4 and the electrode film 52. It is not necessary to form the light-transmitting conductive layer 51 with a transparent conductive material, but to form a metal reflective layer 900 made of a metal material. As shown in FIG. 5, a portion of the photons not absorbed by the photoelectric generating body 4 are reflected by the metal. The layer 900 is reflected and then enters the photovoltaic body 4 to increase light utilization.

Referring to Fig. 6, when the double-sided light is received, an anti-reflection layer 901 is formed on the upper electrode 5, as shown in Fig. 6, to increase the light utilization efficiency.

Referring to FIGS. 7 and 8, in this example, the substrate 2 is used as the light receiving surface to receive light on one side or both sides. However, the upper electrode 5 may be used as a light receiving surface to receive light on one side. An anti-reflection layer 902 is formed on the electrode 5, and a reflective layer 903 is formed on the bottom surface of the light-permeable substrate 21. As shown in FIG. 7, the substrate 21 and the reflective layer 903 constitute the substrate 2'. The photons which are not absorbed by the photoelectric generating body 4 are reflected by the reflecting layer 903 and are absorbed by the photoelectric generating body 4, thereby increasing the light utilization efficiency; and when the upper electrode 5 is used as the light receiving surface and is single-sidedly received. When the substrate 21' is made of an opaque substrate such as a ruthenium substrate, a stainless steel substrate, or a metal substrate (such as molybdenum, aluminum, copper, etc.), the bottom surface of the substrate 21' does not need to be formed, for example. The reflective layer 903 shown in Fig. 7 is as shown in Fig. 8.

In addition, it can be additionally noted that a buffer layer for reducing photocharge recombination rate to increase photocurrent generation may be formed between the first and second type semiconductors 41 and 42 of the photoelectric generating body 4, and the buffer layer is selected from the group consisting of cadmium sulfide ( CdS), indium trisulfide (In ₂ S ₃ ), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc oxide (ZnO), manganese zinc oxide (ZnMgO), aluminum hydroxide (In(OH) ₃ ) A material such as indium selenide (In ₂ Se ₃ ) or tin dioxide (SnO ₂ ) forms a heterojunction; or is selected from amorphous silicon (a-Si) and microcrystalline silicon. , μc-Si), polycrystalline silicon (poly-Si) and other materials constitute a homojunction.

Referring to FIG. 9, a second preferred embodiment of the solar cell of the present invention having electrodes of micron or sub-scale conductive lines is similar to the first preferred embodiment except that the conductive lines 32" are respectively The conductive particles 33 having a majority of the average particle diameter of the micron order or less are connected to each other and randomly formed and irregularly distributed, so that the conductive wires 32" are regarded as the number of the conductive particles 33 connected in a string, and the length is not formed. In the form of one, but at least a portion of each of the conductive wires 32" is connected to the substrate 31.

Referring to FIG. 10, preferably, after the conductive particles 33, a conductive film 34 is formed, for example, by using a chemical vapor deposition method, a physical vapor deposition method, an electrochemical plating method, or the like, and then the photoelectric generation body. 4 is formed on the conductive film 34, the conductive film 34 makes the conductive particles 33 more easily connected to each other to form the conductive lines 32", thereby improving the efficiency of the overall photocurrent output, wherein the conductive film 34 is selected It is made of materials such as indium tin oxide, indium zinc oxide or aluminum zinc oxide.

It should be particularly noted that the conductive wires 32" are first mixed with a plurality of conductive particles 33 having an average particle diameter of nanometers into a solvent, and then the solution is spin-coated, coated, and sprayed. , a spray, or a combination thereof, after forming a coating film on the substrate 31, and then removing the solvent, and a part of the conductive particles 33 and the substrate 31 naturally form a gap. 6. The void 6 is isolated from the outside after the photo-electric generating body 4 is formed, and is not formed in the void 6 when the light-transmitting conductive layer 51 is formed, thereby causing a defect in electrical abnormality of the element. In this example, The electrically conductive particles 33 may be selected from transparent conductive materials selected from the group consisting of indium tin oxide, indium zinc oxide, aluminum zinc oxide, or the like, or selected from the group consisting of iron, cobalt, nickel, copper, indium, tin, zinc, gold, silver, and aluminum. Conductive metal materials such as manganese are formed by spraying.

In summary, the present invention has a solar cell having electrodes of micrometer- or micro-scale or less conductive lines. Compared with the conventional thin-film solar cell 1, the present invention forms the conductive lines on the substrate 31 of the lower electrode 3. The three-dimensional structure of 32 reduces the moving distance of the charge carriers excited by the photo-generated body 4 after absorbing the photons, thereby reducing the probability of the electron carriers being combined into the electron-hole pairs during the movement of the charge carriers in the photoelectric generating body 4, thereby greatly increasing the probability Overall photocurrent output performance.

Furthermore, since the surface of the photoelectric generating body 4 is substantially uneven and has a high and low undulating surface, the photon is increased by increasing the illuminating area compared with the conventional thin film solar cell 1. The probability that the body 4 excites the charge carriers is greatly increased, and the three-dimensional structure of the lower electrode 3 is matched to improve the overall power generation efficiency, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2‧‧‧Substrate

2'‧‧‧Substrate

2"‧‧‧Substrate

21‧‧‧Substrate

21'‧‧‧Substrate

22‧‧‧Anti-reflective layer

3‧‧‧ lower electrode

31‧‧‧Substrate

32‧‧‧Flexible wire

32’‧‧‧Flexible wire

32”‧‧‧Flexible wire

33‧‧‧Electrical particles

34‧‧‧Electrical film

4‧‧‧Photoelectric generator

41‧‧‧First type semiconductor

42‧‧‧Second type semiconductor

43‧‧‧Dye absorption layer

5‧‧‧Upper electrode

51‧‧‧Light conductive layer

52‧‧‧Electrode film

900‧‧‧Metal reflector

901‧‧‧Anti-reflective layer

902‧‧‧Anti-reflective layer

903‧‧‧reflective layer

904‧‧‧reflective layer

Figure 1 is a schematic cross-sectional view showing the current thin film solar cell;

Figure 2 is a cross-sectional view showing a first preferred embodiment of the solar cell of the present invention having electrodes of micron or micron or less;

Figure 3 is a cross-sectional view showing the different conductive lines in the first preferred embodiment of the present invention;

Figure 4 is a plan view of an embodiment of the upper electrode in the first preferred embodiment;

Figure 5 is a cross-sectional view of the first preferred embodiment;

Figure 6 is a cross-sectional view of the first preferred embodiment;

Figure 7 is a cross-sectional view of the first preferred embodiment;

Figure 8 is a cross-sectional view of the first preferred embodiment;

Figure 9 is a cross-sectional view showing a second preferred embodiment of the solar cell of the present invention having electrodes of micron or micron or less; and

Figure 10 is a cross-sectional view of the second preferred embodiment of Figure 9 for assistance.

2. . . Substrate

twenty one. . . Substrate

twenty two. . . Antireflection layer

3. . . Lower electrode

31. . . Substrate

32. . . Conductive wire

4. . . Photoelectric generator

41. . . First type semiconductor

42. . . Second type semiconductor

43. . . Dye absorption layer

5. . . Upper electrode

51. . . Light-transmissive conductive layer

52. . . Electrode film

Claims (8)

A solar cell having an electrode of a micron or less conductive line, comprising: a substrate comprising a light transmissive substrate, and a surface formed on the substrate for reducing light reflection during illumination An anti-reflection layer that increases the probability of light entering; the lower electrode is formed of a conductive material on the substrate opposite to the anti-reflective layer, including a substrate, and most of the conductive lines of the micron or sub-scale are each A conductive wire is a substrate whose one end is connected to the lower electrode, and the other end forms a free end; a photoelectric generating body is formed upward from the substrate and covers the conductive wires, and is generated by a photovoltaic effect when illuminated. The photocurrent includes a first type semiconductor and a second type semiconductor which are doped to form a junction structure, and a dye absorbing layer interposed between the first type semiconductor and the second type semiconductor, the dye absorbing layer is illuminated The probability that the junction structure absorbs photons is increased; and an upper electrode is formed on the photoelectric generating body and is electrically conductive, and the lower electrode cooperates with each other to output the photocurrent to the outside. A solar cell having an electrode having a micron- or micro-scale conductive wire according to claim 1, wherein the conductive wires are connected to the substrate in an upright manner. A solar cell having an electrode having a micron- or micro-scale conductive wire according to claim 2, wherein the conductive wire is formed on the substrate by anodizing to have a size of micron. A plurality of pore-shaped aluminum oxide films of a grade or less are formed by removing the aluminum oxide film by forming a conductive material in the holes. A solar cell having an electrode having a micron- or micro-scale conductive wire according to claim 1, wherein the conductive wires are substrates which are connected upward and angularly to the lower electrode. The solar cell of the electrode having a micron or sub-micron conductive wire according to claim 1, wherein the conductive wires are respectively connected to each other by a plurality of conductive particles having an average particle diameter of a micron order or less. form. A solar cell having an electrode having a micron- or micro-scale conductive wire according to claim 5, wherein the conductive wire is a conductive particle having a majority of the average particle diameter of a micron order or less After mixing into a solvent to form a solution, the solution is formed by forming a coating film on the substrate by spin coating, coating, spraying, spraying, or a combination thereof, and then removing the solvent. A solar cell having an electrode having a micron or micron level of a conductive wire according to claim 6, wherein the photogeneration body comprises a first type semiconductor and a second layer which are doped to form a junction structure a type semiconductor, and a dye absorbing layer interposed between the first type semiconductor and the second type semiconductor, the dye absorbing layer increasing the probability of the junction structure absorbing photons when illuminated. A solar cell having an electrode having a micron or sub-micron conductive wire according to claim 7 wherein the substrate comprises a light transmissive substrate, and one of the substrates is formed opposite to the substrate Lower electrode An anti-reflective layer on the bottom surface that reduces light reflection during illumination to increase the probability of light entering the photo-generation body.